KR20190081737A - Loop coil array and wireless power transfer system for train using the same - Google Patents

Abstract

Disclosed by the present invention are a loop coil array device and a wireless power transmission system for train using the same. A central loop coil array has a first resonant frequency higher than an operating frequency for wireless power transmission and enables a magnetic field to be sent father by being sent for wireless power transmission and amplifying the magnetic field incident on itself. A peripheral loop coil array surrounds the central loop coil array in a loop shape to include the central loop coil array, has a second resonant frequency lower than an operating frequency for wireless power transmission, and reduces the amount of leakage flux by attenuating the magnetic field sent for wireless power transmission and incident on itself. The loop coil array device can be arranged between a power transmission coil and a power reception coil. The central magnetic flux of the magnetic field generated by the power transmission coil is amplified to increase transmission efficiency to the power reception coil, and reduces leakage flux by attenuating peripheral flux. The loop coil array device is able to reduce the use amount of ferrite in the wireless power transmission system.

Description

TECHNICAL FIELD [0001] The present invention relates to a loop coil array device and a radio power transmission system for a train using the loop coil array device.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless power transmission or wireless charging technique, and more particularly, to a loop coil array device capable of selectively amplifying and attenuating a magnetic field and a radio power transmission system for a train using the same.

Wireless charging using wireless power transmission has been applied to various products for the purpose of eliminating the power line when charging the product for the convenience of the user. In addition to mobile phones, electric toothbrushes, vacuum cleaners, automobiles, etc. can be easily found throughout the life, the target is continuously increasing. In recent years, studies have been actively conducted to apply wireless charging to a light rail using a large electric power. This can be a solution to the stability and cost issues of traditional power supply line management.

Today, most electric railways use electric pantographs to supply electric power from the transmission line above the vehicle. However, there is a concern that the transmission line is worn out due to the friction occurring at the contact portion between the pantograph and the transmission line, and therefore, it must be managed continuously. However, there is a lot of maintenance cost for continuous maintenance. For this reason, in recent years, there has been an increasing tendency to introduce wireless power transmission technology into railroad.

Wireless power transmission technology transmits electric power mainly using magnetic fields without using wires. That is, the wireless power transmission is a technique of wirelessly transmitting power between two coils of a power transmission coil (primary coil) and a power receiver coil (secondary coil) using magnetic induction phenomenon or magnetic resonance phenomenon. This is a field that is actively researched because it is not directly exposed to current and is a great advantage of safety.

Generally, a wireless power transmission system to be applied to a railway uses hundreds of kilowatts of electric power, and the amount of electric current to be used is several hundreds of A. Since such a large current is used, a strong electromagnetic field is generated around the current in proportion to the magnitude of the current, which may cause various problems. Therefore, shielding the leaked electromagnetic field is emerging as a new problem.

Conventionally, the problem is solved by using ferrite which is an electromagnetic shielding material in a railway system. However, ferrite is a very expensive water, and its price is expensive and heavy. Also, since the amount of ferrite required for shielding is proportional to the magnitude of the magnetic field to be shielded, a large amount of ferrite is required for a railway using large power, which also leads to cost and weight problems.

An object of the present invention is to provide a loop capable of selectively amplifying and attenuating a magnetic field by combining a ferrite and a loop coil array to amplify a magnetic flux in a central magnetic flux of a magnetic field and attenuate a flux in an outer magnetic flux, And to provide a coil array device.

Another object of the present invention is to provide a wireless power transmission system capable of improving the wireless power transmission efficiency while minimizing the leakage magnetic flux by selectively amplifying and attenuating the magnetic field by arranging such a loop coil array device between the power transmission coil and the power reception coil will be.

Another object of the present invention is to provide a radio power transmission system for a train capable of minimizing a leakage magnetic flux while selectively amplifying and attenuating a magnetic field to transmit a large amount of power required for a railway vehicle in operation in a wireless manner with high efficiency.

The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit and scope of the invention.

To achieve the first object, a loop coil array apparatus according to embodiments of the present invention includes a substrate, a central loop coil array, and an outer loop coil array. Wherein the central loop coil array comprises a plurality of first unit loop coil cells disposed adjacent to one another in a central region on the substrate and having a first resonant frequency higher than the operating frequency for wireless power transmission, Amplifies the magnetic field incident on itself and makes it move farther away. Wherein the outer loop coil array includes a plurality of second unit loop coil cells annularly surrounding the central loop coil array and disposed adjacent to each other in an outer region on the substrate, The second resonant frequency is lowered to reduce the leakage flux by attenuating the magnetic field incident on itself by being sent out for wireless power transmission.

In an exemplary embodiment, the resonance frequency of each of the plurality of first unit loop coil cells is not greater than the maximum operating frequency for radio power transmission by no more than 10%, and the resonance frequency of each of the plurality of second unit loop coil cells May be no more than 10% less than the operating frequency for the wireless power transmission.

In an exemplary embodiment, each of the plurality of first unit loop coil cells includes a first conductor coil and a first capacitor connected to each other, and each of the plurality of second unit loop coil cells is connected to a second conductor coil And a second capacitor. The inductance of the first conductor coil is lower than the inductance of the second conductor coil and the capacitance of the first capacitor is lower than the capacitance of the second capacitor The first resonance frequency may be higher than the second resonance frequency by design.

In an exemplary embodiment, the first conductor coil and the second conductor coil may each be made by winding a Ritz wire.

In an exemplary embodiment, the first conductor coil and the second conductor coil are wound using the same conductor wire, and the number of turns of the first conductor coil may be smaller than the number of turns of the second conductor coil have.

In an exemplary embodiment, the plurality of first unit loop coil cells of the central loop coil array are arranged close to each other in the form of a square matrix, and the plurality of second unit loop coil cells of the outer loop coil array are They may be arranged close to each other in the form of a square ring surrounding the square matrix shape.

According to another aspect of the present invention, there is provided a wireless power transmission system including a transmission unit, a reception unit, and a loop coil array module. The power transmission unit includes a power transmission coil for supplying a magnetic field with a current of a predetermined frequency, and transmits power through the power transmission coil. The power receiver includes a power receiving coil spaced apart from the power transmission coil so that the magnetic field can be bridged, and the power transmitted from the power transmission unit is wirelessly transmitted through the power receiving coil. Wherein the loop coil array module is disposed between the power transmission coil and the power reception coil so as to amplify the central magnetic flux among the magnetic fluxes of the magnetic fluxes to be transmitted from the power transmission coil to transmit more magnetic flux amount to the power reception coil, Minimize leakage rate by attenuating.

In an exemplary embodiment, the power transmission unit is installed between two rails of a railroad track, and the power receiver is installed at the bottom of a railway car running on the two rails, And may be disposed so as not to be closer to the power reception coil than the power transmission coil.

In the exemplary embodiment, the power transmission unit further includes a first ferrite plate for shielding a magnetic field, which is disposed on the back side of the power transmission coil and minimizes leakage of the magnetic field emitted from the power transmission coil by the magnetic flux focusing function to the rear and side The power receiver may further include a second ferrite plate for shielding a magnetic field disposed on a rear side of the power receiving coil to minimize leakage of the magnetic field to the rear side and the side of the power receiving coil by the magnetic flux focusing function.

In an exemplary embodiment, the loop coil array module comprises: a substrate; And a plurality of first unit loop coil cells arranged adjacent to each other in a central region on the substrate, the first unit loop coil cell having a first resonance frequency higher than an operating frequency for wireless power transmission, A central loop coil array for amplifying a magnetic flux amount reaching the power reception coil to further enhance the magnetic flux amount to reach the power reception coil; And a plurality of second unit loop coil cells annularly surrounding the central loop coil array and disposed adjacent to each other in an outer region on the substrate, And an outer loop coil array having a frequency and attenuating a magnetic field incident on the transmission coil to reduce the magnetic flux incident thereto and reducing the leakage flux leakage to the outside without reaching the power reception coil.

In an exemplary embodiment, the resonance frequency of each of the plurality of first unit loop coil cells is not greater than the maximum operating frequency for radio power transmission by no more than 10%, and the resonance frequency of each of the plurality of second unit loop coil cells May be no more than 10% less than the operating frequency for the wireless power transmission.

In an exemplary embodiment, each of the plurality of first unit loop coil cells includes a first conductor coil and a first capacitor connected to each other, and each of the plurality of second unit loop coil cells is connected to a second conductor coil A second capacitor,

The inductance of the first conductor coil is lower than the inductance of the second conductor coil and the capacitance of the first capacitor is lower than the capacitance of the second capacitor The first resonance frequency may be higher than the second resonance frequency by design.

In an exemplary embodiment, the first conductor coil and the second conductor coil are wound using the same Ritz wire, and the number of windings of the first conductor coil may be smaller than the number of windings of the second conductor coil have.

In an exemplary embodiment, the plurality of first unit loop coil cells of the central loop coil array are arranged close to each other in the form of a square matrix, and the plurality of second unit loop coil cells of the outer loop coil array are They may be arranged close to each other in the form of a square ring surrounding the square matrix shape.

In an exemplary embodiment, the length of one side of the central loop coil array may not be smaller than the diameter of the power transmission coil.

The loop coil array apparatus 100 according to the present invention can amplify the central magnetic flux of the input magnetic field and attenuate the outer magnetic flux. If this is arranged between the power transmission coil and the power reception coil of the wireless power transmission system, the magnetic field generated in the power transmission coil can be amplified and transmitted to the power reception coil, thereby improving the efficiency of wireless power transmission. At the same time, leakage flux can be reduced by weakening the outgoing magnetic flux. Such a system can be useful for railway wireless power transmission systems, which require high currents to be flowed into transmission coils to deliver large amounts of power wirelessly. In the railway wireless power transmission system, not only the system transmission efficiency but also the shielding effect is good, so a small amount of ferrite can be used, so that the cost and weight can be reduced at the same time.

1 is a plan view of a loop coil array device according to an embodiment of the present invention.
Fig. 2 shows the configuration of the wireless power transmission system and the selective amplification and attenuation of the magnetic field of the loop coil array device disposed between the power transmission coil and the power reception coil, according to the embodiment of the present invention, employing the loop coil array device of Fig. Lt; / RTI >
Fig. 3 shows the configuration of a radio power transmission system for a train and the selective amplification of the magnetic field of the loop coil array device disposed between the power transmission coil and the power reception coil, in accordance with the embodiment of the present invention employing the loop coil array device of Fig. And an attenuation principle.
Fig. 4 shows a magnetic flux distribution of a magnetic field in a radio power transmission system for a train in which the loop coil array device of Fig. 1 is not employed, as a comparative example of the present invention.
5A and 5B are graphs showing impedance magnitudes and phases of a magnetic field amplification coil disposed at the center of the loop coil array device of FIG.
6A and 6B are graphs showing impedance magnitudes and phases of a magnetic-field shielding coil disposed in an outer frame of the loop coil array device of FIG.
7 is a graph showing impedance magnitudes and phases of a loop coil array including a magnetic field amplifying coil and a shielding coil.
FIG. 8 shows a variation of the power transmission efficiency when the position of the loop coil array device of FIG. 1 is different between the power transmission coil and the power reception coil.

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a plan view of a loop coil array device 100 according to an embodiment of the present invention.

1, a loop coil array device 100 includes a substrate 120, a central loop coil array 130 disposed in a central region on the substrate 120, and a plurality of central loop coil arrays 130, And an outer sub-loop coil array 140 disposed in the outer region on the substrate 120 while surrounding the sub-

The substrate 120 may be provided with two loop coil arrays 130 and 140 to physically support the substrate. Any substrate of any material can be used as long as it can do this. For example, a plastic substrate such as an acrylic substrate, or other insulating substrate may be used as the substrate 120.

The central loop coil array 130 may include a plurality of first unit loop coil cells 110-1. The plurality of first unit loop coil cells 110-1 may be disposed adjacent to each other in a central region on the substrate 120. [ The plurality of first unit loop coil cells 110-1 may be densely arranged in a matrix form of N x N as shown in FIG. The plurality of first unit loop coil cells 110-1 may have a first resonant frequency higher than an operating frequency for wireless power transmission. Accordingly, the plurality of first unit loop coil cells 110-1 can be transmitted for wireless power transmission, and can amplify and output the magnetic field incident on the first unit loop coil cells 110-1. Accordingly, the strength of the magnetic field passing through the plurality of first unit loop coil cells 110-1 can be increased and the distance to be covered can be further increased.

The outer loop coil array 140 may include a plurality of second unit loop coil cells 110-2. The plurality of second unit loop coil cells 110-2 may be arranged adjacent to each other in an outer area on the substrate 120 in a ring shape so as to enclose the central loop coil array 130. [ The plurality of second unit loop coil cells 110-2 may be arranged in a square ring shape so as to completely enclose the plurality of first unit loop coil cells 110-1 arranged in a square arrangement, for example. The plurality of second unit loop coil cells 110-2 may have a second resonant frequency lower than the operating frequency for wireless power transmission. Accordingly, the plurality of second unit loop coil cells 110-2 can be transmitted for wireless power transmission to attenuate the magnetic field incident on the second unit loop coil cell 110-2, thereby reducing the leakage flux amount.

According to the exemplary embodiment, the resonance frequency of each of the plurality of first unit loop coil cells 110-1 is designed so as to have a value suitable for the use condition within a range not greater than 10% . The resonance frequency of each of the plurality of second unit loop coil cells may be designed to have a value suitable for the use condition within a range not less than 10% maximum than the operating frequency for wireless power transmission.

According to an exemplary embodiment, each of the plurality of first unit loop coil cells 110-1 may include a first conductor coil 112-1 and a first capacitor 114-1 connected to each other. Similarly, each of the plurality of second unit loop coil cells 110-2 may include a second conductor coil 112-2 and a second capacitor 114-2 connected to each other. The first conductor coil 112-1 and the first capacitor 114-1 may be connected in series. The second conductor coil 112-2 and the second capacitor 114-2 may also be connected in series.

One way to ensure that the first resonant frequency has a higher value than the second resonant frequency is if the inductance of the first conductor coil 112-1 is greater than the inductance of the second conductor coil 112-2 It can be designed to have a low value. According to an exemplary embodiment, the first conductor coil 112-1 and the second conductor coil 112-2 may be made by winding the Ritz wire, respectively. The RITZ wire has a large current capacity, which is advantageous for flowing a large current. That is, the Ritz wire is very suitable for a railroad wireless power transmission system 30 that transmits power using a high current of several hundred A because of the high allowable current. The first conductor coil 112-1 and the second conductor coil 112-2 may be wound using the same conductor wire, in which case the number of windings of the first conductor coil 112-1 is greater than the number of turns of the second conductor coil 112-1, The number of windings can be reduced. This winding can be one way to ensure that the first resonant frequency has a higher value than the second resonant frequency.

As another method for making the first resonance frequency higher than the second resonance frequency, the capacitance of the first capacitor 114-1 is set to a value lower than the capacitance of the second capacitor 114-2 .

2 illustrates a configuration of a wireless power transmission system 200 according to an embodiment of the present invention.

Referring to FIG. 1, the wireless power transmission system 200 may include the loop coil array device 100, the power transmission unit 310, and the power receiver 340 shown in FIG.

The power transmission unit 310 includes a power transmission coil 220 that transmits a magnetic field by flowing a current of a predetermined frequency and can transmit power wirelessly through the power transmission coil 220.

The power receiving unit 340 includes a power receiving coil 240 disposed so as to face the power transmitting coil 220 so as to face the magnetic field transmitted from the power transmitting coil 220, Can be received wirelessly.

The loop coil array device 100 is disposed between the power transmission coil 220 and the power reception coil 240 in parallel. The loop coil array apparatus 100 can provide a selective amplification and attenuation function of a magnetic field which amplifies the central magnetic flux with respect to the incident magnetic field and attenuates the outer peripheral magnetic flux. FIG. 2 also shows selective amplification and attenuation principle for the magnetic field of the loop coil array device 100. FIG. 2, the loop coil array apparatus 100 amplifies the central magnetic flux 260 among the magnetic fluxes of the magnetic fluxes to be transmitted from the transmission coil 220 so that more magnetic flux 262 is transmitted to the power reception coil 240 . On the other hand, the loop coil array apparatus 100 can minimize the magnetic flux amount 272 leaked outward by attenuating the outer frame magnetic flux 270 among the magnetic fluxes of the magnetic fluxes transmitted from the power transmission coil 220.

According to the exemplary embodiment, the power transmitting unit 310 is disposed on the back side of the power transmission coil 220, and has a magnetic flux shielding function for minimizing the leakage of the magnetic field, which is transmitted from the power transmission coil 220 by the magnetic flux focusing function, And may include a first ferrite plate 230. Similarly, the power receiver 340 is also disposed on the rear side of the power receiving coil 240, and the second ferrite plate 250 for shielding the magnetic field, which minimizes leakage of the magnetic field to the rear side and the side of the power receiving coil 240 by the magnetic flux focusing function, . ≪ / RTI >

The power transmission unit 310 may include an inverter 320 that converts transmission power to alternating current and supplies the alternating current to the power transmission coil 220. The power receiver 340 may include a converter 350 that converts an alternating current induced in the power reception coil 240 to a direct current by a linkage with a magnetic field transmitted from the power transmission coil 220. The operation and configuration of the inverter 320 and the converter 350 in the wireless power transmission are well known, and are not directly related to the central idea of the present invention, and a description thereof will be omitted here.

FIG. 3 shows a configuration of a radio power transmission system 300 for a train employing the loop coil array apparatus 100 of FIG. 1 according to an embodiment of the present invention.

The train radio power transmission system 300 applies the radio power transmission system 300 of FIG. 2 to the railway and the train 380. The power transmission unit 310 may be installed between two rails 386 of the railroad track through which the railroad car 380 passes. The power receiver 340 may be installed at the bottom portion 382 of the railroad car 380 running on the two rails 386.

The loop coil array apparatus 100 may be installed so as to protrude downward from the bottom portion 383 of the railway vehicle 380 and to be disposed side by side between the power transmission coil 220 and the power reception coil 240. It is preferable that the loop coil array device 100 is disposed closer to the power reception coil than the power transmission coil 220 in order to efficiently acquire the selective amplification and attenuation effect of the magnetic field. When the central loop coil array 130 is in the form of a square matrix, it is preferable that the length of one side thereof is not smaller than the diameter of the power transmission coil 220.

The first ferrite plate 230 for shielding the magnetic field may be disposed on the back side of the power transmission coil 220 and the second ferrite plate 250 for shielding the magnetic field may be disposed on the back side of the power reception coil 240. The leakage magnetic flux shielding function of these ferrite plates 230 and 250 is as described in FIG.

4 shows a magnetic flux distribution of a magnetic field in a general train radio power transmission system 300-1 which does not employ the loop coil array device 100 of Fig. 1 as a comparative example of the present invention. A typical wireless power transmission system 300-1 includes a transmission coil 220, a power reception coil 240, and a ferrite plate 230, 250 disposed behind each of the power transmission coils 220 and the power reception coils 240 . This is the same as the wireless power transmission system 300 of the present invention.

The wireless power transmission system 300 of the present invention can apply the loop coil array device 100 to the system 300-1 to help the magnetic field to be formed more effectively at the operating frequency of 60 kHz of the system. As described above, the loop coil array apparatus 100 includes a plurality of first and second unit loop coil cells 110-1 and 110-2. When the magnetic field from the power transmission coil meets the central loop coil array 130, a magnetic field is generated that strengthens the magnetic field. As a result, the amplified magnetic field is focused on the power reception coil 240. When the flux is applied to the outer loop coil array 140 among the magnetic fluxes of the magnetic fluxes emitted from the power transmission coil 220, a magnetic field is generated that cancels the magnetic field. As a result, the magnetic field decreases and does not spread out much. That is, the leakage magnetic flux amount is reduced. The ferrite plates 230 and 250 disposed behind the power transmission coil 220 and the power reception coil 240 serve to shield the magnetic field emitted to the rear of the power transmission coil 220 and the power reception coil 240.

By inserting the loop coil array device 100 between the power transmission coil 220 and the power reception coil 240, the amount of ferrite used can be reduced and the efficiency of wireless power transmission can be further improved. In addition, it is possible to obtain a higher power transmission efficiency with respect to the same size of the transmission and reception coils 220 and 240. In addition, a system that reduces the size of the transmission and reception coils 220 and 240 during the same distance wireless power transmission It has the advantage that it can be implemented.

The central loop coil array 130, which helps to focus the magnetic field from the power transmission coil 220 to the power reception coil 240, is loop coils painted with a green background color in FIG. In the figure, a total of four loop coils form a 2x2 array and are located in the middle region.

The outer loop coil array 140 cancels the magnetic field generated by the transmission coil 220 to reduce the leakage magnetic field, while the central loop coil array 130 helps amplify the magnetic field to achieve high power transmission efficiency. . The outer loop coil array 140 is loop coils painted in red in Fig. Thus, even if the first unit loop coil cell 110-1 and the second unit loop coil cell 110-2 physically have the same size, they can play different roles, that is, the role of amplifying the magnetic field, The first unit loop coil cell 110-1 and the second unit loop coil cell 110-2 have different resonance frequencies, which are electrical characteristics.

According to the Faraday rule for electromagnetic induction, when a magnetic field enters a loop coil and is interlinked, an induction voltage is generated in the loop coil, and an induced current flows, thereby forming a magnetic field. The magnetic field thus formed is opposite to the magnetic field entering the loop coil. Even if the induction coil is a coil having pure inductance component or a capacitance component, if the inductance component is very large, a current which forms a magnetic field opposite to the Faraday's law flows in the induction coil as described above. This is the principle of attenuating the magnetic field applied by the outer loop coil array 140. Alternatively, if the loop coil has a capacitance component in addition to the inductance component, a magnetic field having the same direction as the applied magnetic field may be formed when a magnetic field is applied to the loop coil. This is the principle that the central loop coil array 130 amplifies the applied magnetic field.

On the basis of this principle, a first second unit loop coil cell 110-1 which performs an amplification action on a magnetic field by utilizing a conductor wire such as a Ritz wire and a lumped capacitor, and a second unit The loop coil cell 110-2 can be designed. The capacitor and the RITZ wire are used to configure the unit loop coil cells 110-1 and 110-2 and the resonance thereof can be used to set the resonance near the operating frequency of the wireless power transmission system 300. [ The resonance frequency of the unit loop coil cells 110-1 and 110-2 is set to be lower or higher than the operating frequency of the wireless power transmission system 300, (Related to the outer loop coil array 130 having a magnetic field attenuating function) and a region in which the inductance is mainly seen (related to the outer loop coil array 140 having a magnetic field attenuating function).

5A and 5B illustrate the impedance magnitude and phase of the central loop coil array 130 (also referred to as a 'magnetic field amplification loop coil') disposed at the center of the loop coil array apparatus 100 of FIG. FIG.

5A and 5B show the impedance magnitude and phase of each unit loop coil cell 110-1 of the central loop coil array 130 that performs the magnetic field amplification action. The magnetic field amplification loop coil 130 may be designed to have an operating frequency of the wireless power transmission system 300, e.g., 60 kHz, a resonance frequency of about 2 to 5 kHz higher. As can be seen from the graph, when a magnetic field of 60 kHz frequency is input, the magnetic field amplification loop coil 130 operates in the amplification region to amplify the incoming magnetic field. Eventually, a current that creates a magnetic field of the same phase as the incoming magnetic field flows through the amplifying coil. Therefore, in the case of the magnetic-field-amplifying loop coil 130, it can be seen that it is located between the power transmission coil 220 and the power reception coil 240, thereby contributing to enhancement of power transmission efficiency. Even if the distance between the power transmission coil 220 and the power reception coil 240 is long, the use of the magnetic field amplification loop coil 130 pro- vides higher efficiency than when the power transmission coil 220 is not used.

6A and 6B show the impedance magnitude and phase of the outer loop coil array 140 (also referred to as a 'magnetic shield loop coil') disposed in the outer frame of the loop coil array device of FIG. Graph.

The impedance magnitude and phase of the magnetic-field-shielding loop coil 140 are shown in FIG. In contrast to the design of the magnetic field amplification loop coil 130, the magnetic field shield loop coil 140 may be designed to have a resonant frequency that is lower than the operating frequency of the wireless power transmission system 300, e.g., 60 kHz, about 2 to 5 kHz . Then, the magnetic field shielding loop coil 140 operates in the shielded area as shown in FIG. 6 at the operating frequency of the wireless power transmission system 300, for example, 60 kHz. This causes the magnetic-field-shielding loop coil 140 to create a magnetic field in the opposite direction of the magnetic field entered into it, thereby canceling the input magnetic field, resulting in the effect of magnetic shielding. Accordingly, the magnetic-field shielding loop coil 140 may be disposed at the outer periphery of the loop coil array device 100, such as the red area of Fig. 1, to be used to cancel the leakage magnetic field.

The magnetic-field-shielding loop coil 140 can be constructed only from a Ritz wire having only basic inductance based on Faraday's law. However, in the exemplary embodiment of the present invention, it is possible to configure the combination of the capacitor and the Ritz wire. The reason why the capacitors are used together is to obtain a lower impedance size. If the impedance of the coil is large, even if the same voltage is applied, a low current flows and a higher shielding effect can not be obtained. According to the embodiment of the present invention, it is necessary to recognize that a high current is required for a higher shielding effect, and in order to obtain a high current, each second unit loop coil cell 110-2 of the magnetic- Capacitor 114-2 can be mounted to make the resonance of the loop coil.

For effective amplification and shielding of the magnetic field as described above, it is important to obtain a low impedance size. This requires low impedance while utilizing amplification or shielding. Therefore, it is preferable to set a higher frequency within about 10% of the operating frequency of the wireless power transmission system 300 (for example, 60 kHz) to maximize the amplification effect. Also, setting a lower frequency within about 10% of the operating frequency (eg 60kHz) is a good fit for maximizing the shielding effect. The unit loop coil cell having a resonance frequency exceeding the range of 10% greater than the operating frequency of the wireless power transmission system 300 has a relatively low absolute value of the impedance of the loop coil, So that the amplifying effect or shielding effect on the input magnetic field is lowered. Therefore, it is desirable to set the resonance frequencies of the first and second unit loop coil cells 110-1 and 110-2 within the range of 10% of the operating frequency in order to maximize the effect while operating in the shielding region or the amplification region .

The first and second unit loop coil cells 110-1 and 110-2 having the two kinds of resonances and having different roles are physically identical in size. However, the first and second unit loop coil cells 110-1 and 110-2 are formed by using a conductor wire (e.g., The resonance value can be adjusted. Usually, the value of the capacitor is lumped, so it is effective to control the number of turns of the conductor wire (Ritz wire) for finer resonance frequency adjustment. However, even if you change the electrical characteristics of either the capacitor or the conductor wire (Ritz wire), you can use it without any problem in setting the above resonance.

The design conditions using the inductance of the conductor wire (Ritz wire) and the capacitance of the capacitor can be divided into two methods: a method of adjusting the inductance value by the number of turns of the inductance of the Ritz wire and a method of using a rudder capacitor having different values. Since the inductance of the Ritz wire has a characteristic proportional to the square of the number of turns, the inductance value can be effectively controlled even if the number of turns is increased or decreased slightly. For example, in the case of a shielded region having a resonant frequency lower than the operating frequency of the wireless power transmission system 300, the number of turns of the conductor wire is reduced by 10 turns, and in the case of the amplification region having a resonant frequency higher than the operating frequency, The number of turns of the conductor wire can be reduced by 9 turns. By varying the number of turns in this manner, it is possible to design the loop coil to operate in the amplification region and the shielding region, respectively. Since a capacitor is generally manufactured as a commercialized product, it is possible to design a unit loop coil cell having a low resonance frequency by using a relatively high capacitance. When a relatively low capacitance is used, A unit loop coil cell can be designed.

7 is a graph showing impedance magnitudes and phases of a loop coil array including a magnetic field amplifying coil and a shielding coil.

FIG. 7 is a view of FIG. 5 and FIG. 6 in a single view. It can be seen from the phase graph of FIG. 7 (B) that the magnetic field amplifying loop coil 130 and the magnetic field shielding loop coil 140 respectively form a magnetic field having a phase difference of 180 degrees from each other at an operating frequency of 60 kHz . As a result, it can be seen that the magnetic field amplifying loop coil 130 forms the same magnetic field as the direction of the incoming magnetic field, and the magnetic field shielding loop coil 140 forms a magnetic field opposite to the direction of the incoming magnetic field. By arranging the two loop coils 130 and 140 in one array, it is possible to obtain a loop coil array device 100 that performs amplification and attenuation with respect to an input magnetic field.

2, the wireless power transmission system 300 to which the loop coil array device 100 is applied is shown such that the loop coil array device 100 is located at a midway point between the power transmission coil 220 and the power reception coil 240 . Depending on the application, it may be difficult to arrange at such a position in reality. When the loop coil array apparatus 100 is disposed closer to the transmission coil 220 side, high power transmission efficiency can be maintained. This can be confirmed by the following experiment.

8 shows a case where the loop coil array device 100 is positioned at the midpoint between the power transmission coil 220 and the power reception coil 240 when the loop coil array device 100 is not applied (diamond) And a graph showing power transmission efficiency according to a distance between the power transmission coil 220 and the power reception coil 240 when the loop coil array device 100 is positioned closer to the power transmission coil (triangle). When the distance between the power transmission coil 220 and the power reception coil 240 is short, the effect of the loop coil array device 100 is relatively small. However, as the distance between the power transmission coil 220 and the power reception coil 240 increases, The effect of increasing the efficiency of the coil array device 100 is large. It can be seen that there is not much difference in efficiency when the loop coil array apparatus 100 is located between the transmission coil 220 and the power reception coil 240 and when the loop coil array device 100 is located closer to the transmission coil 220. The loop coil array device 100 installed at the center of the power transmission coil 220 and the power reception coil 240 may be difficult to manufacture when actually commercialized. In such an application, it is easier to implement and can maintain the desired performance if it is disposed closer to the transmission coil 220 side.

The present invention can be used for wireless power transmission or wireless charging. Furthermore, it can be used in various applications in which the distribution of the magnetic field needs to be transformed into a desired shape.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (15)

Board;
And a plurality of first unit loop coil cells disposed adjacent to each other in a central region on the substrate and having a first resonant frequency higher than an operating frequency for wireless power transmission, A central loop coil array that amplifies the magnetic field to move further; And
And a plurality of second unit loop coil cells annularly surrounding the central loop coil array and disposed adjacent to each other in an outer region on the substrate, the second unit loop coil cell having a second resonant frequency And an outer loop coil array for transmitting the wireless power and reducing a magnetic flux incident on the outer coil loop to reduce a leakage flux amount. The method of claim 1, wherein the resonance frequency of each of the plurality of first unit loop coil cells is not greater than a maximum of 10% of the operating frequency for the radio power transmission, and the resonance frequency of each of the plurality of second unit loop coil cells is Is not less than 10% greater than the operating frequency for the wireless power transmission. [2] The apparatus of claim 1, wherein each of the plurality of first unit loop coil cells includes a first conductor coil and a first capacitor connected to each other, and each of the plurality of second unit loop coil cells includes a second conductor coil connected to each other, 2 capacitors,
The inductance of the first conductor coil is lower than the inductance of the second conductor coil and the capacitance of the first capacitor is lower than the capacitance of the second capacitor And the first resonance frequency is higher than the second resonance frequency by being designed. 4. The loop coil array device according to claim 3, wherein the first conductor coil and the second conductor coil are each formed by winding a Ritz wire. 5. The apparatus according to claim 3 or 4, wherein the first conductor coil and the second conductor coil are wound using the same conductor wire, and the number of turns of the first conductor coil is greater than the number of turns of the second conductor coil Wherein the loop coil array device is small. The method according to claim 1, wherein the plurality of first unit loop coil cells of the central loop coil array are arranged close to each other in the form of a square matrix, and the plurality of second unit loop coil cells of the outer loop coil array are arranged in the square And are arranged close to each other in the form of a square ring surrounding the matrix shape. And a transmission coil for transmitting a magnetic field by flowing a current of a predetermined frequency, the transmission unit wirelessly transmitting power through the transmission coil;
And a power receiving coil disposed to face the power transmission coil so as to face the power transmission coil so that the magnetic field can be bridged with each other, the power receiver for wirelessly receiving electric power transmitted from the power transmission unit through the power reception coil; And
Wherein the magnetic flux of the magnetic flux emitted from the power transmission coil is amplified so that more magnetic flux is transmitted to the power receiving coil while the magnetic flux of the outer flux is attenuated to increase the leakage flux amount Wherein the loop coil array module includes a loop coil array module that minimizes the loop coil array module. 8. The railway vehicle according to claim 7, wherein the power transmission unit is installed between two rails of a railway track, and the power receiver is installed at a bottom of a railway car running on the two rails, Wherein the power transmission coil is disposed so as to protrude downward from the power transmission coil and is disposed closer to the power reception coil than the power transmission coil. 9. The magnetic field shielding first ferrite plate according to claim 7 or 8, wherein the power transmission portion is disposed on the back side of the power transmission coil and has a first ferrite plate for shielding a magnetic field minimizing leakage of the magnetic field, Shielding second ferrite plate disposed on the back side of the power reception coil and minimizing the leakage of the magnetic field from the rear side and the side of the power reception coil by the magnetic flux focusing function Gt; 9. The loop coil array module according to claim 7 or 8,
Board; And a plurality of first unit loop coil cells arranged adjacent to each other in a central region on the substrate, the first unit loop coil cell having a first resonance frequency higher than an operating frequency for wireless power transmission, A central loop coil array for amplifying a magnetic flux amount reaching the power reception coil to further enhance the magnetic flux amount to reach the power reception coil; And a plurality of second unit loop coil cells annularly surrounding the central loop coil array and disposed adjacent to each other in an outer region on the substrate, And an outer loop coil array having a frequency and attenuating a magnetic field incident on the transmission coil to reduce the leakage flux leakage to the outside without reaching the power reception coil. system. The method of claim 10, wherein the resonance frequency of each of the plurality of first unit loop coil cells is not greater than the maximum operating frequency for the radio power transmission by more than 10%, and the resonance frequency of each of the plurality of second unit loop coil cells is Is not less than 10% greater than the operating frequency for the wireless power transmission. The apparatus of claim 10, wherein each of the plurality of first unit loop coil cells includes a first conductor coil and a first capacitor connected to each other, and each of the plurality of second unit loop coil cells includes a second conductor coil 2 capacitors,
The inductance of the first conductor coil is lower than the inductance of the second conductor coil and the capacitance of the first capacitor is lower than the capacitance of the second capacitor And the first resonance frequency is higher than the second resonance frequency by being designed. 11. The method of claim 10, wherein the first conductor coil and the second conductor coil are wound using the same Ritz wire, and the number of windings of the first conductor coil is smaller than the number of windings of the second conductor coil Wireless power transmission system. 11. The method of claim 10, wherein the plurality of first unit loop coil cells of the central loop coil array are arranged close to each other in the form of a square matrix, and the plurality of second unit loop coil cells of the outer loop coil array are arranged in the square And are arranged close to each other in the form of a square ring surrounding the matrix shape. 11. The wireless power transmission system according to claim 10, wherein a length of one side of the central loop coil array is not smaller than a diameter of the transmission coil.

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